Oral care chewing gums and method of use

ABSTRACT

The present invention pertains to a method for providing dental hygiene which method employs a low moisture chewing gum or confectionery product containing as active ingredients, a combination of sodium bicarbonate and casein phosphopeptide-amorphous calcium phosphate. The invention also concerns the chewing gums and confectionery products that can provide dental health benefits and methods for their preparation.

This application claims priority to provisional application Ser. No.60/126,032 Filed: Mar. 25, 1999

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention concerns a method for promoting dental hygiene inparticular by reducing plaque, whitening teeth, preventing toothdemineralization and providing tooth remineralization. The methodemploys a chewing gum or confectionery product containing as activeingredients, a combination of sodium bicarbonate and caseinphosphopeptide-amorphous calcium phosphate. The invention also concernsthe chewing gums and confectionery products that can provide dentalhealth benefits and methods for their preparation.

2. Description of the Prior Art

The formation of dental caries in teeth has been well studied. Cariesare understood to result from the accumulation of plaque on the teethand the production of organic acids (plaque acids) when plaquemicroorganisms ferment sugars and starches in food. Before being washedaway by saliva, the acids accumulate in the plaque long enough to lowerthe pH and to cause some of the enamel, a calcium-phosphorous mineralknown as hydroxyapatite, to dissolve, that is, demineralize, which canlead to dental caries (tooth decay), and sensitivity.

Plaque itself which is a sticky film of the oral bacteria and theirproducts, can become calcified with the ultimate formation of a hardmineral on the teeth. Calculus, or tartar as it is sometimes called, isthe solid, hard mass of calcified material deposited on and adhering tothe surfaces of the teeth. As mature calculus develops it becomesvisibly white or yellowish in color. Plaque formation can lead togingivitis and subsequent periodontal disease.

Efforts have been made over the years to address the problem of plaqueaccumulation and the dissolution or demineralization of tooth enamel andthe resultant formation of dental caries.

It is known to use sodium bicarbonate (NaHCO₃), in dental care for thepurpose of reducing plaque and whitening teeth, and further for reducingoral malodor. Also known as baking soda or bicarbonate of soda orcarbonic acid monosodium salt, sodium bicarbonate has long been used indentrifrices such as pastes and oral rinses, often in combination withsodium chloride. It can buffer plaque acids, which causedemineralization of teeth, by returning the oral pH to a more favorablepH. In high concentrations, it is bactericidal against most periodontalpathogens. Sodium bicarbonate has found recent favor over alternativesfor its low cost, safety if ingested, low abrasivity due to its highsolubility, and compatibility with fluoride. Sodium bicarbonate has beenused in chewing gums as a filler, a buffer, a dental plaque remover, asan abrasive when used in higher amounts.

U.S. Pat. No. 3,590,120 teaches a chewing gum containing a dental plaqueremoval agent and a dental polishing agent. Sodium bicarbonate is taughtas a dental plaque removal agent. U.S. Pat. No. 4,170,633 discloseschewing gums for delivering alkyl sulfates as plaque inhibiting agents.Sodium bicarbonate is used as a buffer. U.S. Pat. No. 4,952,407 teacheschewing gums for reducing dental plaque containing glycerol monolaurate. Sodium bicarbonate is used as a filler. U.S. Pat. Nos.5,702,687, 5,693,334, 5,618,517, and 5,629,035 teach chewing gums fordental care which contain organically encapsulated sodium bicarbonate.

Casein phosphopeptides-amorphous calcium phosphate complexes are knownto have anticariogenic teeth strengthening effects when used asdentrifrices. The complexes, also known as CPP-ACP complexes or calciumcasein peptone-calcium phosphate are amorphous calcium phosphatestabilized by casein phosphopeptides. CPP-ACP depresses demineralizationand enhances remineralization while buffering plaque acid. It acts bylocalizing calcium and phosphate ions in dental plaque at the toothsurface. This increased level of calcium and phosphate in dental plaquehelps buffer plaque acid and maintain a state of supersaturation ofcalcium and phosphate in solution. i.e. in the saliva. The use of caseinphosphopeptides alone for prevention of caries and plaque formation isalso known. The use of chewing gum as a carrier for CPP-ACP has beensuggested.

U.S. Pat. Nos. 5,130,123 and 5,227,154 teach casein phosphopeptides inprevention of dental caries. WO 98/40406 teaches phosphopeptide-calciumphosphate complexes to provide anti-caries efficacy.

While it would be very desirable to combine in one delivery system theplaque reduction and tooth whitening benefits of sodium bicarbonate withthe remineralization and strengthening of teeth provided by CPP-ACP, itis known that sodium bicarbonate will react with calcium phosphate toform calcium carbonate. Combining sodium bicarbonate with CPP-ACP, wouldbe expected to precipitate calcium carbonate thereby diminishing thesupply of calcium ions and concomitantly diminish the efficacy ofCPP-ACP. A combination of the two dental care components in a systemsuch as traditional oral rinses and pastes, would result in adiminishing or deactivation of the remineralization efficacy of theCPP-ACP.

SUMMARY OF THE INVENTION

The present invention concerns a method for providing dental hygienewhich method employs a low moisture chewing gum comprising:

-   -   (a) from about 10% to about 95% by weight gum base,    -   (b) from about 0.1% to about 15% by weight of sodium        bicarbonate, and,    -   (c) from about 0.01% to about 30% by weight of CPP-ACP.

The present invention further concerns a method for providing dentalhygiene which employs a low moisture confectionery product comprising:

-   -   (a) from about 10% to about 95% by weight confectionery base,    -   (b) from about 0.1% to about 15% by weight of sodium        bicarbonate, and,    -   (c) from about 0.01% to about 30% by weight of CPP-ACP.

The invention also concerns the chewing gums and confectionery productscontaining the active ingredients.

DETAILED DESCRIPTION OF THE INVENTION

The present invention, as stated above, concerns low moisture chewinggums and confectionery products which reduce plaque, whiten teeth,prevent tooth demineralization and provide tooth remineralization in theoral cavity. The chewing gums and confections contain as activeingredients, a combination of sodium bicarbonate and caseinphosphopeptide-amorphous calcium phosphate complexes. The presentinvention overcomes the problem of combining the ingredients in an oraldelivery system by use of a low moisture, solid system such as a chewinggum or a confection. By a low moisture chewing gum or confection ismeant one that contains less than 2% moisture. The chewing gum is alsopreferably sugarless.

In the chewing gums and confections of the present invention theingredients cannot admix prior to use by the consumer, that is, couldnot admix upon storage. The chewing gum and confections in effect“compartmentalize”. i.e. separate the two components. In a furtherembodiment of the invention each component could be in a separate anddiscrete layer of gum or confection. In still another embodiment of theinvention one or both of the components could be encapsulated to preventcontact until the gum or confection is consumed.

The chewing gums and confections may contain from 0.1% to 15% by weightof sodium bicarbonate and from 0.01% to 30% by weight of CPP-ACP. It ispreferred to use from 0.1% to 10% by weight of sodium bicarbonate andfrom 0.01% to 10% by weight of CPP-ACP. For chewing gums it is desirableto have the CPP-ACP and sodium bicarbonate present in a weight ratio ofapproximately 1:5.

Chewing gums, because of prolonged contact with the oral cavity in use,and due to the fact that a gum base can provide for sustained release ofthe active components, provide an excellent delivery system for theactive ingredients and are preferred. The invention also concernsconfections, in particular candy confections, especially pressed candyconfections. Conventionally pressed candy confections such as tabletscontain about or less than 0.5% moisture and provide an excellentdelivery system for the active ingredients.

Manufacture of chewing gums and confections such as pressed tablets arewell known and are taught in E. B. Jackson, Ed. “Sugar ConfectioneryManufacture”. 2nd edition. Blackie Academic & Professional Press.Glasgow UK, (1990), at pages 259 and 236 respectively, and in R. Lee andE. B. Jackson, Eds. “Sugar Confectionery and Chocolate Manufacture”,Chapman and Hall, UK. (1992), at pages 332 and 286 respectively.

The chewing gum can be any convenient formulation. The gum formulationcan be sugar free or it can contain sugar. It generally comprises one ormore natural or synthetic elastomers which is supplemented byconventional chewing gum ingredients. These ingredients include one ormore solvents, plasticizers, fillers, flavoring agents, coloring agentsand/or sweetening agents. Elastomers which are suitable for use hereininclude substances of vegetable origin such as chicle, jelutong, guttapercha, guayale and crown gum. Synthetic elastomers such asbutadiene-styrene copolymers, isobutylene-isoprene copolymers,polyethylene, polyisobutylene, polyvinylacetate, and mixtures thereofare also useful. The elastomer generally comprises from about 14% to 50%by weight, preferably from about 20% to about 30% by weight, of thechewing gum composition. Polyvinyl acetates may also be used with theelastomers to provide stretch or elasticity to the gum.

The chewing gum composition can contain elastomer solvents to aid insoftening the polymer component. Such elastomer solvents can includemethyl, glycerol or pentaerythritol esters of rosins or modified rosins,such as hydrogenated, dimerized or polymerized rosins or mixturesthereof. Terpene resins, including polyterpene and mixtures thereof arealso useful. The solvent can be employed in an amount ranging from about10% to 75% and preferably about 15% to about 50% by weight of thechewing gum composition.

A variety of traditional ingredients used as plasticizers or emulsifierssuch as lanolin, lecithin, glycerol monostearate, stearic acid, glyceroltriacetate, triacetin, glycerine and the like can also be incorporatedinto the chewing gum composition to obtain a variety of textures andconsistency properties. These additional materials also include waxessuch as natural waxes, petroleum waxes and microcrystalline waxes andfats and oils including animal fats such as lard and tallow, vegetableoils such as soybean and cottonseed oil, hydrogenated and partiallyhydrogenated vegetable oil and cocoa butter. These ingredients aregenerally employed in amounts of up to about 30% by weight, preferably1% to 25% by weight and more preferably from about 3% to about 7% byweight of the final chewing gum composition.

The chewing gum composition can additionally include conventionalcoloring agents such as titanium dioxide, in amounts up to 2% andfillers such as dicalcium phosphate, magnesium carbonate, aluminumhydroxide, alumina, aluminum silicates, talc, calcium carbonate,cellulose, and combinations thereof in amounts of from 5 to 35% byweight of the final composition.

The chewing gum composition may also contain bulk sweeteners includingsugars such as sucrose, dextrose, maltose, fructose and the like orsugar alcohols such as sorbitol, mannitol, xylitol, maltitol, isomalt,cryihritol and hydrogenated starch hydrolysates and combinationsthereof. Bulk sweeteners may be present in amounts up to 90% by weightof the final composition. High intensity sweeteners such as aspartame,acesulfame salts, aliatame saccharin and the like may also be present.These sweeteners may be present in amounts of up to 1% by weight of thefinal gum composition.

The chewing gum may contain flavoring agents in addition to the enhancedflavoring compositions in amounts up to 3.5%. Generally any foodadditive such as those described in “Chemicals Used In Food Processing”,publication 1274, pages 63-258, by the National Academy of Sciences, maybe used.

The chewing gum is generally manufactured by methods known in the art bysequentially adding the various chewing gum components to any commercialmixer or extruder in a batch or continuous process. After theingredients have been thoroughly mixed the mass is discharged andformed.

The preparation of confectionery formulations is historically well knownand has changed little through the years. In general a hard boiled candyconfection has a base composed of a mixture of sugar and othercarbohydrate bulking agents kept in an amorphous or glassy conditionhaving from about 0.5% to about 5% moisture. In the present applicationthe moisture content is 2% or less. The base normally contains up toabout 75% sugar (sucrose) and up to 65% corn syrup, with a highersucrose to corn syrup ratio. Further ingredients such as flavoringagents, sweetening agents, acidulants, colorants and so forth may alsobe added. Hard boiled candies may also be prepared from non-fermentablesugars such as sorbitol, mannitol, xylitol, maltitol, erythritol,hydrogenated starch hydrolysates and the like. A general discussion ofthe composition and preparation of hard confections may be found in E.B. Jackson, Ed. “Sugar Confectionery Manufacture”. 2nd edition, BlackicAcademic & Professional Press, Glasgow UK, (1990), at pages 129-169.

Such confectionery may be routinely prepared by conventional methodssuch as those involving fire cookers, vacuum cookers, andscraped-surface cookers also referred to as high speed atmosphericcookers. Once the candy mass has been properly tempered, it may be cutinto workable portions or formed into desired shapes. A variety offorming techniques may be utilized depending upon the shape and size ofthe final product desired.

Soft candy confectionery includes fondants, caramels toffees, fudge,marshmallows and nougats and the like and may also include jams andjellies. The preparation of soft confections, such as nougat, involvesconventional methods, such as the combination of two primary components,namely (1) a high boiling syrup such as a corn syrup, or the like, and(2) a relatively light textured frappe, generally prepared from eggalbumin, gelatin, vegetable proteins, such as soy derived compounds,milk derived compounds such as milk proteins, and mixtures thereof.Further ingredients such as the enhanced flavoring agent, flavoringagents, additional carbohydrate bulking agent, colorants, preservatives,medicaments, mixtures thereof and the like may be added thereafter alsounder agitation. A general discussion of the composition and preparationof such confections may be found in E. B. Jackson. Ed. “SugarConfectionery Manufacture”. 2nd edition. Blackie Academic & ProfessionalPress. Glasgow UK. (1990), at pages 170-235.

Compressed tablet confections, a preferred embodiment, containparticular materials and are formed into structures under pressure.These confections generally contain sugars or sugar substitutes inamounts up to about 95%, by weight of the composition, and typicaltablet excipients such as binders and lubricants as well as the enhancedflavoring agent, flavoring agents, colorants and so forth.

The following examples are provided to illustrate the preferredembodiments of the invention.

EXAMPLE 1

This example shows precipitation of calcium carbonate upon mixing sodiumbicarbonate with CPP-ACP under conditions which mimic mixing the twocomponents in the environment of the oral cavity for a brief contactperiod and under prolonged contact time.

The amount of CPP-ACP and sodium bicarbonate combined for the test werebased upon an in vivo pre-test done to determine how much CPP-ACP andsodium bicarbonate would be expected to be extracted into the oralcavity, upon chewing, from a gum containing CPP-ACP and sodiumbicarbonate in a 1:5 weight ratio present at approximately 1% CPP-ACPand 5% sodium bicarbonate.

The in vivo test was done to first determine the release of CPP-ACP. Afive person panel chewed a gum containing 1% CPP-ACP. Release of CPP-ACPwas determined as 2.43 mg/ml. Using this data and assuming a similarrelease for sodium bicarbonate, the concentrations of CPP-ACP and sodiumbicarbonate released into the oral cavity were determined to be 0.30%CPP-ACP and 2% sodium bicarbonate for a final CPP-ACP concentration=3mg/ml. CPP-ACP and sodium bicarbonate at these concentration wereincubated in a 30 ml pooled human saliva with moderate shaking at 37° C.for 3 minutes to test precipitation upon consumption of the gum and at 1hour to show how longer contact time would precipitate calciumcarbonate. The resultant pH of the incubation solution was approximately7. The solution was filtered, the retentate was rinsed with deionizedH₂O to remove any soluble calcium and the result was analyzed forcalcium content by Atomic Absorption analysis. As a control an aqueoussolution of 30 g of a 0.3% CPP-ACP solution was pass through the filterpaper. 0.3 mg of precipitated calcium was noted. Also, the sameexperiment was repeated for saliva and a 2% sodium bicarbonate solutionand 1.7 mg of calcium was retained by filter paper. The incubation of0.3% CPP-ACP with 2% sodium bicarbonate in 30 g saliva for 3 min.resulted 2.5 mg calcium retained by the filter paper which calculates asabout 0.5 mg calcium precipitation. The insoluble calcium accounted for3.7% of total CPP-ACP precipitated in 3 minutes. Using the samecalculation for the 1 hour incubation, 15.6% of CPP-ACP interacted andprecipitated.

The following table shows the results of various test periods:

Calcium Test retained 30 g of aqueous solution with 0.3% CPP-ACP 0.300mg 30 g of saliva with 2% NaHCO₃ stored at 37° C. for 3 minutes 1.700 mg30 g of saliva with 0.3% CPP-ACP and 2% NaHCO₃ stored at 2.500 mg 37° C.for 3 minutes 30 g of saliva with 2% NaHCO₃ stored at 37° C. for 1 hour1.600 mg 30 g of saliva with 0.3% CPP-ACP and 2% NaHCO₃ stored at 4.000mg 37° C. for 1 hour

The test showed that approximately 4% of the 1% of CPP-ACP is consumedin 3 min. and approximately 16% of the 1% in 1 hr. A concomitantreduction in activity could be expected. The result indicates that forthe short period of time needed to release CPP-ACP and sodiumbicarbonate from a chewing gum into the oral cavity (a 10 min. chewingof a gum containing 1% CPP-ACP and 5% of sodium bicarbonate) CPP-ACP hasa very small probability of losing efficacy. However, as expected,interactions of the sodium bicarbonate and CPP-ACP increase with alonger time exposure, which may indicate is potential loss of CPP-ACPefficacy during shelf storage in the presence of moisture.

EXAMPLE 2

This example shows the efficacy of CPP-ACP in remineralization when usedin a chewing gum containing CPP-ACP and sodium bicarbonate in the weightratio of 1:5. A pellet-type chewing gum was formulated as follows:

Pellet Gum: INGREDIENT % Gum Base 30.77 Softeners 0.23 Polyols 61.05Intense Sweeteners 0.21 Flavors 1.57 Sodium Bicarbonate 3.76 CPP-ACP0.71 Gum Arabic 1.70The gum had a total delivery size (two pieces) of 2.9 g providingapproximately 20.6 mg CPP-ACP.

The gum was used in a test designed as a two-week product usage,double-blind, four-way crossover test with a one week rest between thecrossover tests. A sugarfree gum formulated without the actives was usedfor comparison. The gums were chewed four times per day for 20 minuteseach chewing. The test subjects met minimums for salivary flow rate. Aremovable palatial appliance with human-enamel, half-slab insetscontaining subsurface demineralized lesion was used. The other half ofeach enamel slab was stored and used as the control demineralizedlesion. Appliances were worn by subjects during gum chewing and 20minutes after chewing. At the completion of each treatment the enamelslabs were removed, paired with their respective demineralized controland the enamel remineralization was measured by microradiography todetermine the percent of remineralization of the test enamel slab vs.the demineralized enamel slab. The following table shows the resultantmean percent remineralization. Also provided for comparison is the meanpercent remineralization obtained for a gum containing solely CPP-ACP asthe active. (This gum delivered 18.8 mg of CPP-ACP. The inventive gumcontaining 20.6 mg had an approximate 10% overage.)

Percent Remineralization: Test: CPP-ACP/Sodium Control (No Gum)Sugarfree Gum Bicarbonate Gum 2.499 ± 0.41% 9.107 ± 0.42% 18.297 ± 1.85%Comparison: Control (No Gum) CPP-ACP Gum 4.36 ± 1.65% 17.06 ± 2.48%

The results demonstrate that CPP-ACP in the presence of baking sodaresults in significant remineralization when compared with a sugarfreegum as a control. The test further shows that the remineralization isequivalent to that provided by a gum containing CPP-ACP as the active.

1. A method for providing a dental hygiene effect which method comprisesplacing a low moisture chewing gum in the oral cavity comprising: (a)from about 10% to about 95% by weight gum base; and, (b) from about 0.1%to about 15%% by weight of sodium bicarbonate; and, (c) from about 0.01%to about 30% by weight of CPP-ACP wherein the sodium bicarbonate andCPP-ACP are kept separate from each other until chewing; and, chewingthe low moisture chewing gum for a time sufficient to provide saiddental hygiene effect.
 2. The method according to claim 1 wherein thelow moisture chewing gum is a sugarless gum.
 3. The method according toclaim 1 wherein the low moisture chewing gum comprises: (a) from about0.1% to about 10%% by weight of sodium bicarbonate, and, (b) from about0.01% to about 10% by weight of CPP-ACP.
 4. A low moisture chewing gumcomprising (a) from about 10% to about 95% by weight gum base; and, (b)from about 0.1% to about 15% by weight of sodium bicarbonated; and, (c)from about 0.01% to about 30% by weight of CPP-ACP, said sodiumbicarbonate and said CPP-ACP component being separated from each other.5. The gum according to claim 4 wherein the low moisture chewing gum isa sugarless gum.
 6. The low moisture chewing gum according to claim 4wherein the gum comprises: (a) from about 0.1% to about 10% by weight ofsodium bicarbonate; and, (b) from about 0.1% to about 10% by weight ofCPP-ACP.